Fereydoon Abbasi, a nuclear scientist who leads the Atomic Energy Organization of Iran, revealed Monday that one of the attacks occurred mid-August just before international inspectors arrived at the underground site U.S. and Israeli officials said was the most unsusceptible to bombings, The New York Times reported.

The Times said there was no way to independently verify Abbasi's claims made during a speech at an International Atomic Energy Agency conference Monday in Vienna. He also alleged that the U.N. nuclear energy watchdog was infiltrated by "terrorists and saboteurs," intimating they were responsible for the attacks.

Abbasi's accusations came as Israeli Prime Minister Binyamin Netanyahu has been urging U.S. President Obama's administration to set "red lines" as thresholds for action against Iran's nuclear activities. Western countries say they believe Iran is trying to advance its nuclear weapons capability while Tehran says its nuclear activities are for civilian purposes.

Abbasi said Fordow, the underground site near Qum, was one of two sites attacked. He said that power lines from Qum to the site "were cut using explosives" Aug. 17. He said IAEA officials requested "a snap inspection of the facility" early the next day.

Abbasi said a similar attack was carried out at Natanz, an older plant, but didn't provide a date.

United Press International is a leading provider of news, photos and information to millions of readers around the globe via UPI.com and its licensing services.

With a history of reliable reporting dating back to 1907, today's UPI is a credible source for the most important stories of the day, continually updated - a one-stop site for U.S. and world news, as well as entertainment, trends, science, health and stunning photography. UPI also provides insightful reports on key topics of geopolitical importance, including energy and security.